I bought an orange and yellow/lime shells off
eBay for my Lumia 635. The pictures showed matte shells but I received glossy shells instead. Not a big deal. The orange shell is perfect and a genuine OEM, however the lime shell is likely a reject because the buttons are flush with the side, which makes changing volume and locking/unlocking difficult.
Bummer. I have poor luck buying shells off eBay. It's the luck of the draw. Anyway, I submitted a request for refund. It's only $8.99 but it's not what I ordered.
On a side note, I was pleasantly surprised to receive the package one week after ordering it. Not bad for free postage! Usually it takes about a month or so for items to ship from HK and mainland China.